Oscillating power screed



United States Patent lnventor LeRoy O. Kraemer P.0. Box 321, Sturgis, S. Dak. 57785 Appl. No. 717,317 Filed March 29, 1968 Patented Aug. 11, 1970 OSCILLATING POWER SCREED 3 Claims, 4 Drawing Figs.

US. Cl 94/45 Int. Cl E01c 19/22 Field of Search 94/45, 48

[56] References Cited UNITED STATES PATENTS 2,248,247 7/1941 Nichols 94/45 3,008,388 11/1961 Nave 94/48 3,412,658 1 1/1968 Griffen 94/45 3,418,902 12/1968 Wilson 94/45 Primary Exar'niner- Jacob L. Nackenoff Attorney- Berman, Davidson and Berman ABSTRACT: An oscillating power screed comprising: a pair of parallel screeds secured together and spaced from each other by frame members adjacent each end of the screeds and by a central frame member; a lead screed parallel to said firstname screeds and hinged to one of said screeds by a plurality of hinges; power means on said central frame member; an eccentric driven by said power means and a connecting rod between said eccentric and said lead screed.

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length of the machine, of course, corresponds roughly to the OSCILLATING POWER SCREED The free end of the lever extension 74 is connected to a It is a primary object of this invention to provide a power cable 78 which passes around the pulley 80 secured to an screed operative over substantial widths of concrete but which upright 82. The upright 82 is firmly secured to the secondary is light enough to be controlled by one man and require a screed 12 which itself is hinged at 84 to the frame 16. A minimum degree of the P of the Operators I precisely similar arrangement is provided at the frame 18. The

It is a further object of this invention to provide a pair of purpose Qfthe hinge joint 84 will be explained hereinafter. fixed screeds preceded by an oscillating screed which, while at F o h ll 80, th bl 78 run to a pulley 86 secured all times parallel to the fixed screed, nevertheless, performs orbital movement relative thereto.

It is a further object of this invention to provide in the i0 screed as aforesaid means for balancing and rolling the screed as a whole on the edges of the sideboards defining the concrete slab to be smoothed.

- The above and other'objects will be made clear from the following detailed description taken in connection with the annexed drawings, in which:

FIGURE 1 is a top plan view of the improved screed;

FIGURE 2 is a front elevation of the improved screed;

FIGURE 3 is a section on the line 3-3 of FIGURE 2; and

FIGURE 4 is a bottom plan view of the parts shown in FIGURE 3.

Referring now to FIGURE 1, the machine is made up of a lead screed 10 mounted for oscillation, as will behereinafter descibed. There is provided a secondary screed 12 and a final screed 14. The screeds l2 and 14 preferably are simply 2" x 6 timbers extending the full length of the machine. The

to an upright 88 also secured to the secondary screed 12. A similar upright 90 is similarly joined at the opposite side of the frame 42 to the screed 12 and receives a cable 92 from a pul ley 94 mounted on an upright 96 adjacent the frame 18.

A pair of bars 98 and 100 are respectively pivoted to the uprights 86 and 90 and at their free ends are joined by a cross bar 102 providing thereby a handle for general manipulation of the screed.

A rod 104 is pivoted in a cross member of the frame 42 and its free end carries a sleeve 106 in which is pivoted one end of a lever 108. A fixture 110 is'adjustably secured on the lever 108 and receives the free ends of cables 78 and 92. In the position shown in FIGURE 1, the free end of the lever 108 is held by a clamp 112 mounted on the arm 100. In this position, both of the rollers 60 and 62 are held in inactive position by a spring such as 76, best shown in FIGURE 3. Two parallel dotted lines 56 are shown in FIGURE 3. The upper one corresponds to the solid line position of roller 62 and the lower one to the dotted line position. The lever 108 may be disenwidth of the slab to be finished and the travel of the machine is gaged from the clamp.l l2 and i f toward the handle 102 so as to engage an ad ustably positioned clamp 114, also on normal, the screeds lzand the member 100 and in this osition the extension 74 in The screeds 12 and 14 are secured together in spaced rela- FIGURE 3 d d h tionship by end frames 16 and 1s. The lead screed 10 is e f me t e secured to the secondary screed 12 by a series of hinge joints holler 62 f of i i i i the 60) will ar- 20' The hinge joints 20, as best Seen in FIGURES 3 and 4, rive at their dotted line positions bearing on the sideboards 56 comprise plates 22 which in their neutral position are normal and 58 h g the g g 1f f ofcomact wlth the to both the screeds l0 and 12. At each end of a plate 22 is a concrete lymg etween oar S 5 an steel loop 24 surrounding a pintle 26 which passes through choke and throttle controls for the motor 44 may be loops 28 and 30 respectively formed in plates 32 and 40. The mounted conveniently on either of the l or 100 and plates 32 are Seamed to the i Screed 10 and the plates it is not deemed necessary to show these in this disclosure. are secured to the secondary Screed 11 In practice, it is preferred that the leading edge of the screed Approximately midway Ofthe screeds l2 and 14 is mounted 40 10 be vertically spaced from a sixteenth to a thirty-second of a frame 42 which further spaces and rigidifies the screeds 12 Z: 233:; i tfg zz figgiigggz iggg Screed l2 and 14. A motor 44 is mounted on the frame 42 and through a r mixes;i:553933;3511222215.?21122213122: which also has bearing in the frame 42. At the oppos te end of 45 m t th 5 Condar s 12 is hin d as g to the fra S the shaft IS an eccentric 52 which engages and reciprocates 16 d m d 5 d l t th 42 A d 1 2 a connecting rod 54. At its opposite end the connecting rod 54 an ewe 0 e fame to at engages a pin 56 which by means of a bracket 58 is secured to one end firmly engaged the frame 16 and at the other the lead screed 10. n will be apparent from FIGURES 3 and 4 end adjustabiy engaged with uprights and 94 y of and particularly FIGURE 4, that when the intermediate hinge 50 huts when the right-hand hut 118 FIGURE 3 ls backed plate deviates either side of a plane normal to the fixed screed Q and the PP h hut edvahcedg both screeds l0 and 12 are 12 the lead Screed 10 n approach the screed 2 and the tilted about the axis of hinge 84 with the result that the screed retreat from it until plate 22 resumes the neutral position. For lselevated e y higher h the Screed 12, thus accomthis reason, it is best that both ends of the connecting rod have Phshlhg the adlustmeht afore$a1dsome sort of flexible, or ball and socket connection to their 55 In Practice, the Sideboards 56 and y be anywhere respective pins. In addition, the actual stroke can be adjusted m five to twenty feet f P hzfvlhg hand 3 pp by a simple adjustment of the eccentricity of the pin on the ecof Screed boards 12 and It 15 a Simple matter to cheese. centric 52. the proper length of board and to place thereon III the rela- It will be noted in FIGURES 1 and z fm as a tionship shown in FIGURES l and 2, the frames 16, 18 and whole slides on rails 56 and 58' which actujally are boards 0 42, then with the installation of the p p hinges 2 the d fini th id edges f h l b or concrete to b fi i h d; device is ready for operation at the optimum width. It is to be When it is desired to maneuver the machine as a whole, the noted that the X boards Preferred for s r ds 2 and 14 following mechanism is resorted to, and the 1" X 6" board preferred for lead screed 10 are R f ring now to FIGURES l, 3 and 4, there is mounted completely standard and may be obtained with no difficulty in within the frame 16 a roller 60 and within the frame 18 a roller y length from y lumber y 62, A shown i FIGURES 3 d'4, h ll 62 i t t bl While various specific details have been disclosed herein, mounted on an axle 66 which in turn is mounted on opposed qu te obviously many variations on the precise structure levers 68. The levers 68 are mutually joined by a sleeve 70 shown will suggest themselves to anyone studying this-applicawhich bears on an axle 72 mounted in cross members of the tion. It is not, therfore, intended to'lim'it the invention to the frame I6. One of the levers 68 has an extension 74' which ex- 70 precise details disclosed. tends beyond the axle 72 and has adjacent its freeerld aspri-ng Ielfliml 76 connected to a portion of the frame 16 and tending to hol oscillating power screed comprising: a pair of parallel the roll well above the top edge of the sideboard or form 56. .screeds'r'ecu dtqge't'her andspaced'from eachother by frame The arrangement at the opposite'e'nd,forroller62'isprecisely m'em'bers adjacent each end -of..the screeds and by a central--- the same.

1 frameflm ernbery a lead screed 'parallelto said first-named porting roller mounted in each of said end frames and in which each of said rollers is normally biased to inactive position.

3. A screed as set forth in Claim 2. including control members connected to said central frame and a handle member connecting said control members; and means mounted on said control members for bringing said rollers into active position. 

